In the related art, a plasma etching apparatus performs etching using a photoresist as a mask. Here, there is a method for improving characteristics of the photoresist that is used as a mask by the plasma etching apparatus. For example, there is a method for depositing silicon containing deposits as a protective layer on the photoresist by plasma of at least any one of silicon tetrachloride gas and methane gas. See, for example, Japanese National Phase Patent Laid-Open Publication No. 2010-516059 and International Publication No. WO2014/024833.